Lores



M. LoREs 2,605,960

CORRECTOR DEVICE FOR ROENTGENOLOGIC MEASUREMENTS Aug. 5, 1952 Filed March 20, 1951 [N VEN rop.'

ATTORNEJCF,

Aug 5, 1952 M. LORES 2,605,960

CORRECTOR DEVICE FOR ROENTGENOLOGIC MEASUREMENTS Filed March 2o, 1951 2 SHEETS- SHEET 2 L 25 22 la; I. ,7 l\\\\\\\\\\\ ATTORNEyJ.

Patented Aug. 5, 1952 UNITED STATES PATENT OFFICE CORRECTOR DEVICE FOR ROENTGENO- LOGIC MEASUREMENTS This invention relates to .corrector devices for roentgenologic measurements, and particularly it relates to the devices commonly used in roentgenologic cephalopelvimetry for obtaining the accurate and direct determination of any pelvis diameter or distance from the corresponding measurement on the X-ray film.

The device disclosed in this application is based on the geometrical principle that: In similar triangles the bases are directly proportional to their altitudes or heights. Based on this principle and taking advantage of the mathematical fact that any number divided by 100 gives an even decimal, which makes for simpler and more exact calculations, the applicant has devised an easy toy make and to operate calculator device which permits by measuring any pelvic diameter or distance on the X-ray film to accurately determine the corresponding diameter or distance in the human pelvis.

The device of this invention comprises a rec tangular table provided at its base portion with a longitudinal groove in which are mounted three sliding bars in longitudinal alignment, of which sliding bars the first and second carry a transversal film scale strip and a transversal object scale strip respectively, and the third sliding bar has lpivotally mounted thereon a rotating arm adapted to cross the two strip scales referred to. The base edge portion on the table has a'scale divided in centimeters, the resting position of the lm scale on this base scale being determined by the table top-film distance of the X-ray machine in use, and the resting position of the object scale on said base scale being determined by the object-table top distance of the pelvic diameter under consideration. The base edge scale represents the object-table top distance and the anode-'table top distance of the X-ray machine in use. The pivot of the rotating arm represents the anode of the tube of the X-ray machine in use. By adjusting the position of the rst and second strip scales along the table base scale, the position of the pivot of the rotating arm according to the position of the tube when the films are taken and the position of the rotating arm when crossing the first strip scale at the point on which ends the diameter or distance taken on the X-ray nlm, the point on which the rotating arm crosses the second stripv scale determines the exact diameter or distance on the object. Thus, this invention permits to make and operate a simple calculator device for determining any pelvic'diameter or distance from the corresponding measurement on the X-ray nlm.

2 The invention is described by making reference to the gures of the annexed drawings, of which: Fig. 1 is a top plan view of the device forming the subject matter of this invention.

Fig. 2 is a transverse sectional view on line 2 2 of Fig. 1.

Fig. 3 is a transverse sectional view on line 3 3 of Fig. 1,

Fig. 4 is a schematic view showing the positions of the object and the lm on a table to take X-ray photographies and towards which are directed the rays from the tube of an X-ray machine.

This invention is based on the following principle: The rays produced by the Coolidge tube l are directed by the target towards the lm 2 as a cone 3 4. Any object 5 placed parallel to the film 2 in this cone on the top of a table 6 containing the lm 2 in a drawer l below the table top (Fig. 4) creates a shadow, which is reproduced as its image in the X-ray lrn 2. Taking the anode of the tube l as the apex of the two triangles 3 4, 3' 4', the rays passing at the ends 3 4 of the interposed object and at the ends 3 4 of its image as the sides of two similar triangles, the bases o-f which triangles are the object and its image in the iilm 2, the following geometrical equations can be constructed because the bases 3 4 and 3 4 of these triangles are directly proportional to their and as l 8=( I 9) 8 9), by making the corresponding substitution in the above equation, it results:

3 4 1 9 and taking a xed distance cm.-for I 9,

In the above equation, 3 4', the object, represents the pelvic diameter; 3 4 represents its is the factor of magnification. From the last equation one can deduct that the object is directly proportional to its image and to the factor of magnification and because the object-nlm distance 8 9 is the only variable in the factor of magnification, the object 3 4 is also a function of the object-nlm distance 8 9.

Because the object-nlm distance 8 9 is measured in centimeters and 100 is used as a constant for the anode-film distance I S, the factor of magnification decreases by .O1 for every increase in 1 cm. for the object-film distance 8 9; thus an error of 1 cm. in the object-film distance 8 9 represents one of .O1 in the factor of magnification. The same does not hold true for an error in the image 3 4, which is transmitted in direct proportion to the calculation of the object or true diameter 3 4.

Basing on the last equation, I may construct a device comprising a rectangular table I which has fixedly superimposed at its ends two cleats H and I2. the base portion of the table IIl and in this dovetailed groove are lodged three sliding bars of dovetailed cross-section I4, I5 and I6, and on the edge of said base portion of the table Il) is fixed a longitudinal-cleat I'I onA which is marked a scale in centimeters divided in two scale portions, one right scale portion from a point G representing the top surface Grof the table S-and which right scale portion represents the table top-film distance 9 2 of the machine in use, and another left scale portion from the point 0 which is divided in 100 centimeters and which represents the anode-film distance I 9. On the slidingbar I6 is fixed a transversal strip having `a scaie- I8 and on the sliding bar l5 is fixed a transversal strip having a scale I9, both scales lI8 and I9 being divided in centimeters from two points 0 at the same transverse line, On the sliding bar I4 is pivoted by the intermediate of a block 29 having an index 2l at the middle of its base, a rotating arm 22 traversed through a hole 23 by the smooth surfacev of a screw pivot 24 screwed in the sliding bar I4. Thus, the arm 22 canvrotate to beadjusted -in a suitable position on the scale I8 by means of'a hair line 25 with which it is provided andwhich is seen throughthe transparent body of said arm 22.

The operation of the deviceis as follows: As the movable lm scale I8 represents the length or diameter 3 4 of the imageon the film 2, its resting position is determined-by the table toplm distance 9 2 of the machine in use, which is set as an example in 5 centimeters on the right scale portion of the base scale marked on cleat I'I. The movable object scale I9 represents the object diameter 3 4' under consideration, and its resting position is determinedaby thelobjecttable top distance 0 26. The baseY scale portion marked on cleat I'I at the left from the zero represents the table top-anode distance 0 I, and the position of the pivot 24 thereon is determined by the position of the tube anode I when the nlm is taken, and which has been set as 95 centimeters in the example shown in Fig. l.

Then, when the hair line of the rotating arm 22 is adjusted to the measured film diameter 3 4 of the film scale I8, the point where the hair line 25 crossesl the truediameter scale I9 is the figure for the true or corrected diameter 3' 4. l

All diameters, distances and fetal skull circumference in the lateral view take by the X-ray machine on the patient are in the mid-plane, therefore, their object-table top distance is half of the intertrochanteric diameter, as measured directly on the patient, and is the same for all of them.

In calculating thetransverse diameters as mea- A dovetailed grove I3 extends along.

sured in the antero-posterior film, the objecttable top distance of the diameter under consideration is its corrected distance as determined from the lateral film.

The circumferences of the fetal skull and fetal skull diameters are corrected using the same scale that are used for the diameters of the pelvis.

It is evident that the device of this invention may be used for correcting purposes in taking an X-ray photography of any other osseus cavity of human body different from the pelvis, and that certain modifications of this device are possible without altering the essential character of the invention, within the broad scope and spirit of the following claims.

I claim:

l. A corrector device for roentgenologic measurements, comprising a table carrying on its base a scale in length units divided in two opposed scale portions from a common point Zero, one of which scale portions represents the anodetable top distance of the X-ray machine in use.

and the other scale portion represents the table top-film distance of the X-ray machine in use. two-transverse strips spaced apart and slidingly mounted on said table base scale, each strip carryingfa scale in length units, one of the latter scales representing the film diameter and the other representing the object diameter, a bar rotatably mounted by a pivoton a supporting block slidingly mounted on said table base scale, and adapted to cross the scales on said two strips, said pivot representing the tube anode of the X-ray machine-in use, means of adjusting the position of the twostrip scales each on a scale portion of the base scale above mentioned from thepoint zero thereof, and means of adjusting the position of the pivot of the rotatable bar at the upper division end of the base scale portion representing the anode-table top distance of the machine in use.

2. A corrector device for roentgenologic measurements, comprising a table carrying on its base a scale in length units divided in two opposed scale portions from a common point zero, one of which scale portions represents the anodetable top distance of the X-ray machine in useand the other scale portion represents the tabletop film distance of the X-ray machine in use,.

two transverse strips spaced apart and slidingly mounted on said base scale, each strip carrying a scale in length units, the right strip scale representing the film diameter and theleft strip scale representing the object diameter, a bar rotatably mounted by a pivot on a supporting block slidingly mounted on the upper division end of the base scale portion representing the anode-table top distance of the X-ray machine in use and adapted to cross the scales on said two strips, said pivot representing the tube anode of the X-ray machine in use, means of adjusting the position of the two strips each on a scale portion of the base scale'above mentioned and in oppo.

presenting the table top lm distance of the X-ray machine in use and the left scale portion representing the anode-table top distance of the X-ray machine in use, two dovetailed cross-section bars slidingly mounted in said groove and each having secured thereto a transverse strip having a scale in centimeters, of which the right strip scale represents the lm diameter and the left strip scale represents the object diameter, a transparent bar having a hair line and rotatably mounted by a pivot on a supporting block secured to a dovetailed cross-section bar slidingly mounted in said groove in front of the upper division end of the base scale portion representing the anode-table top distance of the X-ray machine in use, said pivot representing the tube anode of this machine, the crossed position of the pivoted bar once superimposed on the two strip 6 scales serving to determine the object diameter from the lm diameter.

MANUEL LORES.

REFERENCES CITED The following references are of record 1n the le of this patent:

UNITED STATES PATENTS 

